Ignition timing change-over device for spark advance mechanism having rotatable governor plate

ABSTRACT

An ignition timing change-over device adapted for use with a spark advance mechanism having a rotatable governor plate. A plunger means is adapted to protrude and rotate the governor plate to an angular position in which an ignition advance occurs during the cold operating conditions of the engine irrespective of the intake manifold vacuum. In one embodiment, the plunger means is actuated to hold the governor plate in the advance position during closure of a starting switch. Another embodiment employs a relay and a thermostatically controlled switch to keep the plunger means in the advance position during the engine warmup operation. A further embodiment comprises a thermostatically operated plunger which is operative to rotate the governor plate through a mechanical linkage during the engine warm-up operation.

United States Patent 1191 Nambu 1 1 Dec. 18, 1973 1 1 IGNITION TIMING CHANGE-OVER 3,494,338 2/1970 Reise 123/ 1 17 A DEVICE FO SPARK ADVANCE 3,621,824 11/1971 Burnia et a1. 123/117 A 1,785,902 12/1930 Hardman 123/117 A MECHANISM HAVING ROTATABLE 3,057,938 10/1962 Perry 123/117 A X [75] Inventor: Shyuya Nambu, Yokohama, Japan [73] Assignee: Nissan Motor Company, Limited,

Yokohama City, Japan 122] Filed: Oct. 22, 1970 [21 1 Appl. No.: 82,868

130] Foreign Application Priority Data Oct. 22, 1969 Japan 44/84541 [52] U.S. CI 123/117 A, 123/179 BG, 123/97 B [51] Int. Cl. F02p 5/10, F02p 5/14 [58] Field of Search 123/179 BO, 117 A,

[56] References Cited UNITED STATES PATENTS 2.809620 10/1957 Boylan 123/117 A 3,876,754 3/1959 Obermaier.... 123/117 A 3,301,242 1/1967 Candelise 123/117 A 3,400,698 9/1968 Kelly 123/117 A GOVERNOR PLATE TO STARTING MOTOR A Primary Examiner-Al Lawrence Smith Att0rneyMcCarthy, Depaoli, O'Brien & Price [57] ABSTRACT An ignition timing change-over device adapted for use with a spark advance mechanism having a rotatable governor plate. A plunger means is adapted to protrude and rotate the governor plate to an angular position in which an ignition advance occurs during the cold operating conditions of the engine irrespective of the intake manifold vacuum. In one embodiment, the plunger means is actuated to hold the governor plate in the advance position during closure of a starting switch. Another embodiment employs a relay and a thermostatically controlled switch to keep the plunger means in the advance position during the engine warm-up operation. A further embodiment comprises a thermostatically operated plunger which is operative to rotate the governor plate through a mechanical linkage during the engine warm-up operation.

4 Claims, 6 Drawing Figures TO IGNlTION COIL PATENIED DEC 1 8 I975 SHEET 10F 4 INVENTOR SH YU YA NAMBU QMNZ we ATTORNEYS PATENIEIIIIEC I 8 I975 IGNITION ADVANCE IGNITION ADVANCE TDC TDC

SIIEET 2 OF 4 STARTING MOTOR SWITCH ON STARTING MOTOR SWITCH OFF TIME TI-IERMOSW l TCH OFF I 6 I TEMPERATURE INVENTOR SHYU YA NAMBU ATTORN EYS PATENIEDBEE 1' 8 ms SHEET t 0F 4 TEMPERATURE Fig.6

INVENTOR BY SHYUYA IVAMBU IMM, M2075;

ATTORNEYS IGNITION TIMING CHANGE-OVER DEVICE FOR SPARK ADVANCE MECHANISM HAVING ROTATABLE GOVERNOR PLATE various measures have been taken including retarding of the ignition timing in a spark ignited internal combustion engine. The retarding of the ignition timing is found most effective during warm-up operation of the engine, to reduce the content of harmful pollutants such as hydrocarbons and nitrogen oxides in automobile exhaust gases. And, it is a usual practice to hold the ignition timing in the neighbourhood of or about five degrees behind top dead center on the compression stroke at idle speed during warm-up operation of the engine although it is most desirable to provide 10 to 18 degrees of ignition advance to give the maximum engine performance or thermal efficiency at that speed unless considerations is given to the reduction of content of the harmful exhaust gases. However, the method of retarding the ignition timing is disadvantageous in that it adversely affects the engine performance during cold starting of the engine. That is, with the ignition timing initially set to behind the top dead center, great difficulties are experienced in starting the engine at the atmospheric temperatures below --1 5 C.

It is, therefore, an object of this invention to provide an ignition timing change-over device which is incorporated in the ignition advance unit, whether it may be of pneumatic or centrifugal type, to improve the engine performance during the engine starting.

It is another object of this invention to provide a plunger means which is capable of advancing the ignition timing to 18 of the crank angle ahead of the top dead center during cold starting of the engine.

In the drawings:

FIG. 1 is a circuit diagram showing, partly diagrammatically, an ignition system according to one embodiment of this invention;

FIG. 2 is a diagrammatical illustration of the ignition advance accomplished by the system of FIG. 1 during the time when the starting switch is closed;

FIG. 3 is view similar to FIG. 1, showing a modification of this invention;

FIG. 4 is a diagrammatical illustration of the ignition advance attained by the system of FIG. 3 during the engine warm-up operation;

FIG. 5 is a fragmentary diagrammatic view showing another modification of this invention; and

FIG. 6 is a view similar to FIG. 4, but shows a gradual change in the ignition timing to the retarded side effected by the unit shown in FIG. 5.

Referring now to FIG. 1, the ignition system as depicted comprises a d.c. voltage source or battery 10, an ignition switch 11, an ignition coil 12, a distributor 13, spark plug wires 14 and spark plugs 15. Also included in the system is a single point breaker 16 having a breaker cam 17 which rotates with the distributed rotor 18 of the distributor 13. The breaker 16 has a set of contact points, one being a movable contact point 19 attached to a contact arm 20 and the other being a stationary contact point 21 connected to ground. The arm 20 is mounted for pivotal movement about a pin 22 in a governor plate 23 to open and close the breaker contact points 19 and 21 by the rotating action of the breaker cam 17. The stationary contact point 21 is also mounted on the governor plate 23. The movable contact arm 20 is shunted by a condenser 24 to ground and connected to the primary side of the ignition coil 12 by way of a resistor 25.

The ignition system includes a conventional vacuum advance unit 26 and governor advance unit (not shown). The vacuum advance unit 26 comprises a housing 27 including a diaphragm 28, a diaphragm connecting link bar 29, and a spring 30 held against the diaphragm 28. One end of the diaphragm connecting link bar 29 is operatively connected to a radially extending end 31 of the governor plate 23 of the breaker 16. A conduit 32 connects the vacuum unit 26 to the intake manifold (not shown).

Positioned adjacent to the breaker 16 is a solenoid means 33 having a plunger member 34 engaged at its tip with the extending end of the governor plate 23 and adapted to rotate the governor plate 23 in a direction to advance the ignition timing 10 to 18 before the top dead center. When the plunger member 34 is projected by energization of the solenoid means 33 during starting of the engine. The solenoid means 33, along with a starting motor (not shown), is electrically connected to the battery 10 by way of a starting switch 35.

Operation of the system is such that when the starting switch 35 is closed to start the engine the plunger member 34 is projected to rotate the governor plate 23 counterclockwise to the angular position which is proper for the engine starting, so that a proper ignition advance is accomplished relative to the normal retarded condition as shown in FIG. 2. Once the engine is started the starting switch 35 is opened to deenergize the solenoid means 33, causing the plunger member 34 to retract thereby rotating the governor plate 23 clockwise to the angular position dependent upon the intake manifold vacuum. With the governor plate 23 in the position an ignition retarding is obtained as shown is FIG. 2. It is to be understood that when the plunger member 34 is actuated the governor plate 23 is rotated thereby irrespective of the intake manifold vacuum.

FIG. 3 illustrates a modification of the system shown in FIG. 1 although the ignition coil and distributorare not shown for the sake of clarity of illustration. In FIG. 3, like parts and components are indicated by the same reference numerals as those shown in FIG. 1.

In the embodiment shown, also, a solenoid means 33 is provided that is adapted to rotate the governor plate 23 of the breaker 16 by a plunger member 34 operatively connected thereto. However, the solenoid means 33 of this arrangement is electrically connected to the battery 10 by way of a relay 37. The relay 37 includes a switch 38 which is normally kept open by spring pressure and a solenoid coil 39 having one end connected to ground and the other to a thermostatically controlled switch 40 which in turn is connected to the battery 10 by way of the ignition switch 11. The thermostatically controlled switch includes a pair of contact members, one of which is of a bimetal plate adapted to warp toward the other contact member, thus coming into contact therewith. The thermostatically controlled switch 40 is so located as to sense the engine temperature, for example, cooling liquid, engine oil, exhaust gases or engine body itself so as to open the relay solenoid circuit when the engine temperature exceeds a predetermined level C. In case of cooling liquid, for example, the switch 40 may be so set as to open when the temperature of the liquid increases to C.

In operation, the ignition switch 11 is closed simultaneously with the closure of the starting switch 35. The solenoid coil 39 of the relay 37 is energized so that the switch 38 connects the solenoid means 33 to the battery 10, causing the plunger 34 to protrude and rotate the governor plate 23 of the breaker 16. Thus, the ignition timing is advanced relative to the normal retarded condition during cold starting of the engine. When the cooling liquid temperature is raised by the engine operation to the value 0, the thermostatically controlled switch 40 opens to de-energize the solenoid coil 39 of the relay 37. As a result, the relay switch 38 opens and the solenoid means 33 is deenergized causing the plunger 34 to be retracted. Thus, the ignition timing is retarded under this normal operating condition of the engine. FIG. 4 diagrammatically shows the relationship between the ignition timing and cooling liquid temperature 0.

FIG.5 shows another modification of the invention comprising a thermostat 42 of the type in which the plunger 43 gradually protrudes as the temperature sensed thereby increases above 6 C. The of the plunger member 43 is transferred to the governor plate 23 of the breaker 16 through a connecting linkage 44. As shown, the connecting linkage 44 comprises an arm member 45 mounted for pivotal movement about a stationary fulcrum 46 and a spring member 47 mounted desirably on the wall of the engine for urging the arm member 45 to rotate in a clockwise direction as viewed in FIG. 5. When the cooling liquid temperature, for example, is below 0 C during the engine warm-up, the plunger member 43 of the thermostat 42 is kept in the retracted position and the spring member 47 urges the arm 45 to be rotated clockwise, rotating the governor plate 23 counterclockwise so that the ignition timing is switched to 10 to 18 ahead of the top dead center of the piston. As described above, when the liquid temperature is increased to 6 C the plunger member 43 is caused gradually to protrude and rotate the arm member 45 counterclockwise against the action of the spring member 47. As a result, the governor plate 23 is rotated clockwise to the angular position dependent upon the intake manifold vacuum, thereby retarding the ignition timing as shown in FIG. 6.

As has been described above, this invention provides an ignition timing change-over device incorporated in the ignition system to electrically or mechanically control the ignition timing so as to improve the engine performance during the engine starting and warm-up.

What is claimed is:

l.-An ignition timing change-over device designed to provide a normal retarded condition during warm-up operation of an internal combustion engine, which is adapted for use with a spark advance mechanism having a rotatable governor plate, said device comprising, in combination,

A. a d.c. voltage source,

B. a relay means electrically connected to said d.c.

voltage source,

C. a solenoid means elecrically connected through said relay means to said d.c. voltage source and having a plunger means provided in abutting engagement with said governor plate for mechanically rotating said governor plate to an angular position that advances the ignition timing ahead of top dead center during cold starting of said engine,

D. a starting switch which electrically connects a starting motor to: 1. said d.c. voltage source, 2. an ignition switch, and 3. said relay means, and

E. a thermostatically controlled switch electrically connected between said d.c. voltage source and said relay means for opening and closing said relay means, said thermostatically controlled switch being responsive to the engine temperature, whereby, when said engine temperature is below a predetermined value during cold starting of said engine, said thermostatically controlled switch closes said relay means thereby energizing said solinoid means to cause said plunger means to rotate said governor plate for thereby advancing said ignition timing relative to the normal retarded condition to increase engine performance efficiency during said cold starting of said engine.

2. An ignition timing change-over device as claimed in claim 1, wherein said relay means includes a normally open switch connected in series between said solenoid means and said d.c. voltage source and a solenoid coil connected in series to said d.c. voltage source through said thermostatically controlled switch for closing said normally open switch when the engine temperature is below the predetermined value during starting condition of the engine.

3. An ignition timing change-over device as claimed in claim 1, wherein said thermostatically controlled switch includes a pair of normally closed contact members, one of which is of a bimetal plate adapted to warp toward the other contact member when the engine temperature sensed thereby is below the predetermined value and to break contact with said other contact member when the engine temperature sensed thereby exceeds said predetermined value.

4. In an ignition system for an internal combustion engine having a spark advance mechanism provided with a rotatable governor plate, an ignition timing change-over device designed to provide a normal retarded condition when cold starting said engine and during warm-up operation thereof, which is adapted for use with said rotatable governor plate, comprising, in combination,

A. a d.c. voltage source,

B. a relay means having 1. a normally open switch connected in series to said d.c. voltage source and 2. a solenoid coil connected in series to said d.c.

voltage source,

C. a solenoid means electrically connected through said relay means to said d.c. voltage source and having a plunger means in abutting engagement with said governor plate for mechanically rotating said governor plate in a direction that advances ignition timing ahead of top dead center during cold starting of said engine,

D. a starting switch which electrically connects a starting motor to:

1. said d.c. voltage source, 2. an ignition switch, and

3. said relay means, said starting switch and said ingition switch being closed simultaneously to start said engine, and

E. a thermostatically controlled switch electrically connected between said solenoid coil of said relay means and said dc. voltage source, said thermostatically controlled switch including a pair of normally closed contact members, one of which pair is of a bimetal plate adapted to warp toward the other contact member when the engine tempera ture sensed thereby is below a predetermined value during engine starting and to break contact with said other contact member when the engine temficiency during cold starting of said engine. 

1. An ignition timing change-over device designed to provide a normal retarded condition during warm-up operation of an internal combustion engine, which is adapted for use with a spark advance mechanism having a rotatable governor plate, said device comprising, in combination, A. a d.c. voltage source, B. a relay means electrically connected to said d.c. voltage source, C. a solenoid means elecrically connected through said relay means to said d.c. voltage source and having a plunger means provided in abutting eNgagement with said governor plate for mechanically rotating said governor plate to an angular position that advances the ignition timing ahead of top dead center during cold starting of said engine, D. a starting switch which electrically connects a starting motor to:
 1. said d.c. voltage source,
 2. an ignition switch, and
 3. said relay means, and E. a thermostatically controlled switch electrically connected between said d.c. voltage source and said relay means for opening and closing said relay means, said thermostatically controlled switch being responsive to the engine temperature, whereby, when said engine temperature is below a predetermined value during cold starting of said engine, said thermostatically controlled switch closes said relay means thereby energizing said solinoid means to cause said plunger means to rotate said governor plate for thereby advancing said ignition timing relative to the normal retarded condition to increase engine performance efficiency during said cold starting of said engine.
 2. an ignition switch, and
 2. an ignition switch, and
 2. a solenoid coil connected in series to said d.c. voltage source, C. a solenoid means electrically connected through said relay means to said d.c. voltage source and having a plunger means in abutting engagement with said governor plate for mechanically rotating said governor plate in a direction that advances ignition timing ahead of top dead center during cold starting of said engine, D. a starting switch which electrically connects a starting motor to:
 2. An ignition timing change-over device as claimed in claim 1, wherein said relay means includes a normally open switch connected in series between said solenoid means and said d.c. voltage source and a solenoid coil connected in series to said d.c. voltage source through said thermostatically controlled switch for closing said normally open switch when the engine temperature is below the predetermined value during starting condition of the engine.
 3. said relay means, and E. a thermostatically controlled switch electrically connected between said d.c. voltage source and said relay means for opening and closing said relay means, said thermostatically controlled switch being responsive to the engine temperature, whereby, when said engine temperature is below a predetermined value during cold starting of said engine, said thermostatically controlled switch closes said relay means thereby energizing said solinoid means to cause said plunger means to rotate said governor plate for thereby advancing said ignition timing relative to the normal retarded condition to increase engine performance efficiency during said cold starting of said engine.
 3. An ignition timing change-over device as claimed in claim 1, wherein said thermostatically controlled switch includes a pair of normally closed contact members, one of which is of a bimetal plate adapted to warp toward the other contact member when the engine temperature sensed thereby is below the predetermined value and to break contact with said other contact member when the engine temperature sensed thereby exceeds said predetermined value.
 3. said relay means, said starting switch and said ingition switch being closed simultaneously to start said engine, and E. a thermostatically controlled switch electrically connected between said solenoid coil of said relay means and said d.c. voltage source, said thermostatically controlled switch including a pair of normally closed contact members, one of which pair is of a bimetal plate adapted to warp toward the other contact member when the engine temperature sensed thereby is below a predetermined value during engine starting and to break contact with said other contact member when the engine temperature sensed thereby exceeds the predetermined value during engine starting, said solenoid coil of said relay means being energized when said contact members of said thermostatically controlled switch are closed, whereby said normally opern switch of said relay means is closed to energize said solenoid means for causing said plunger means of said solenoid means to rotate said ignitiOn timing relative to the normal retarded condition thereof, thereby increasing engine performance efficiency during cold starting of said engine.
 4. In an ignition system for an internal combustion engine having a spark advance mechanism provided with a rotatable governor plate, an ignition timing change-over device designed to provide a normal retarded condition when cold starting said engine and during warm-up operation thereof, which is adapted for use with said rotatable governor plate, comprising, in combination, A. a d.c. voltage source, B. a relay means having 